Flexible coupling



Sept. 12, 1939.

A. KuHNs Er AL FLEXIBLE COUPLING Filed Aug. 29, 1938 Patented septfiz, 1939 UNITED STATES FLEXIaLE coUrLl'NG Austin Kuhns and Emil R.. Gasser, Buffalo, N. Y.,

assignors to Farrel-Birmingham Company lncorporated, Buffalo, Connecticut Application 'August' 29,

' 1 claim.

IThis invention relates to flexible couplings, particularly couplings of the type in which teeth on the ends of .the hubs of axially opposed shafts -mesh with teeth in a coupling frame surrounding 5 the hubs, thistype of coupling being extensively -used in power; transmission systems as for example in the'driving of marine craft propellers from driving sources such as turbines.

Heretofore in couplings of this type, the pril mary setting was such that the teeth on the shaft hubs and within the coupling frame were parallel with each other and driving under heavy conditions resulted in considerable friction between the meshing teeth faces owing to breakl down of the lubricating on 111m which permitted metallic contact ory so-called seizing. t We have discovered that the performance of this type of couplings can be materially improved by an arrangement which will position the driv-" ing and driven teeth at a slight angle with each other to thereby take the benefit of what is known in lubrication as the Kingsbury effect. j.'I'he op eration will be such that as the lfaces of the meshing teeth move in rotation or relatively back 'and forth. during axial displacement of the coupling members, the included angles between thev faces will produce a wedging action on the oil film and build up'the pressure and prevent a breakdown of the oil film and consequently will' prevent seizing of the coupling faces. The beneiicial result will be increase in strength of the oil 'fllinseparating the driving faces, increase in loa'd carryingcapacity, in freedom of motion both axially andto compensate for misalignment. 85 Our improvedarrangement is incorporated in the structure disclosed on the drawing, in which drawing: Y

Figure 1 is a side elevation, partly ln section,v

of a coupling structure;

Figure 2 is a more or less diagrammatic developed view -showing part of the coupling frame gear teeth and the arrangement of the teethY on one of the shaft hubs; f l

Figure 3- is a view similar to Figure 1 showing l a' modified arrangement; and

Figure V4 lis a view like Figure 2 to more clearly 'show the operation of the structure of Figure 3.

" The couplingstructure shown comprises a coupling frame F which\maybe composed of two parts I0 and' II secured together as by bolt I2. At its opposite ends this coupling frame has the internal teeth I3 and I4 respectively, these teeth extending parallel with the axis of the frame.

Ashaft l5 has the hub I6 surrounded by teeth I1 which mesh with the teeth I3 in the coupling N. Y'., a corporation of frame. The shaft I8 has the hub I9 surrounded by teeth 2li which mesh vwith theI teeth I4 of the 'coupling frame. The teeth I1 and` 20 extend parallel with the .axis of the respective, shafts I5, and I8.

In accordance with our improved arrangement `and as shown by Figures 1 and 2 the coupling structure is primarllyset up so that the shafts I5 and I8 have their axes at a slight angle with each other so that the shaft teeth will no longer be parallel with the coupling frame teeth but will be at a slight angle relative thereto.

-The teeth of the coupling frame are of greater axial extent than the teeth on the shaft hubs so that, with the arrangement shown, when' the coupling structure rotates the shaft hub teeth will move in axial direction relative to the coupling -frame teeth. The operationis diagrammatically shown by Figure 2, which shows the cooperation of the teeth I1 and the teeth I3. As the coupling structure rotates each shaft tooth I1 will oscillate axially in engagement with the teeth I3 and, as the faces of the teeth I1 are at an angle with the faces of the teeth I3, the friction drag of the faces on the lubricant will cause the lubri- -cant to be forced or wedged into the tapering l spaces 2l between the teeth toward the narrow end of the spaces tolgenerate a pressure which will tend to hold the faces apart against kmetallic contact or seizing and to maintain an adequate Y lubricating oil film between'the faces, the result being what'is known in lubrication as the Kingsbury effect. i During axial' oscillation onmis alignment of the shaft this Kingsbury eifect will prevent metallic contact or seizing of the meshing teeth. t K the Amodified arrangement of Figures 3 and y 4,l the structure is the same as in Figure 1 except that the teeth I1' an'd 20' on the shaft hubs IBcand I9 respectively are inclined or set at a slight angle with' the shaft axes, or in other v words, these teeth will have a slight helicalangle. With this tooth arrangement, when the coupling structure-.is primarily set, the shafts I5 and I8 may be supported with their axes coincident. With this arrangement, any axial oscillation or displacement of the shafts I5 and I8 relative to each other or .relative to the coupling frame F will result in wedging of the lubricating oil into the tapered spaces 2 betwen the faces of the shaft teeth and the coupling .frame teeth and we will have the Kingsbury effect which will pre- .yent metallic contact or seizure of the teeth. y

l With either arrangement of Figures 1 and 3", as the coupling elements shift or oscillate rela? 55 tively axially during operation of the coupling structure, the Kingsbury eifect resulting from our improved relative arrangement of the teeth will prevent metallic contact or rubbing of the meshing teeth and ample lubricating oil film will be maintained and assured between the -teeth surfaces. With such prevention of metallic rubbing or seizure and the assurance of an .adequate lubricating oil film, the coupling members may move with greater freedom together and relatively with material increase in load carrying capacity.

We have shown a practical and efficient embodiment of our invention but we do not desire to be limited to the exact structure and arrangement shown and described as changes and modications may be made without departing from the scope of the invention.

We claim as follows: Y f

A couplingstructure of the class described comprising a coupling frame having internal teeth extending parallel with the frame axis, shafts ex tending into the ends of said frame and having teeth meshing with the frame teeth, said frame and shafts being adapted for relative axial displacement, the teeth on the shafts extending at 'a slight angle with the respective shaft axes to provide tapering or wedge spaces between the bearing faces of the meshing teeth into whichlubricating oil is forced during operation of the coupling for maintenancel of the lubricating oil nlm and to prevent metallic contact or seizing of the meshing teeth.

AUSTIN KUHNS. EMIL R. GASSER. 

